# US 2023/0054945 A1 · Uv-led radically curable offset printing inks and printing processes

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- Number: US 2023/0054945 A1
- Document ID: US20230054945A1
- Status: Published application
- Kind: A1
- Application number: 17/786,880
- Filed: 2020-12-15
- Published: 2023-02-23
- Earliest claimed: 2019-12-18
- Assignees: Sicpa Holding SA
- Applicants: Sicpa Holding SA
- Inventors: John HOGGETT; Stéphane CHABRIER
- Web page: https://patentgrep.com/patent/US20230054945A1

## CPC

- C09D 11/101: Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
- B41M 3/14: Security printing {(securities B42D25/29)}
- B41M 7/0081: {using electromagnetic radiation or waves, e.g. ultraviolet radiation, electron beams}
- B42D 25/387: absorbing or reflecting ultraviolet light
- C09D 11/03: characterised by features other than the chemical nature of the binder
- C09D 11/037: characterised by the pigment
- C09D 11/107: from unsaturated acids or derivatives thereof
- C09D 11/12: based on waxes or bitumen
- B41M 1/06: Lithographic printing
- B42D 25/29: Securities; Bank notes
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P)
- B42D: BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS

## Abstract

The present invention relates to the field of UV-LED radically curable inks for offset printing of security documents. In particular, the invention relates to UV-LED radically curable offset printing inks for offset printing on a substrate or security document, said UV-LED radically curable inks having a viscosity in the range of about 2.5 to about 25 Pa s at 40° C. and 1000 s−1 and comprising radically curable (meth)acrylate compounds, one or more photoinitiators of formula (I), one or more amino containing compounds selected from the group consisting of aminobenzoate compounds, amine modified polyether based acrylates and combinations thereof, and one or more fillers and/or extenders.

## Claims

### Claim 1

A UV-LED radically curable offset printing ink having a viscosity in the range of about 2.5 to about 25 Pa s at 40° C. and 1000 s−1 for offset printing a feature on a substrate, said UV-LED radically curable offset printing ink comprising:
i) from about 10 wt. % to about 80 wt. % of one or more radically curable (meth)acrylate compounds consisting of one or more radically curable (meth)acrylate oligomers and one or more radically curable (meth)acrylate monomers, said radically curable (meth)acrylate oligomers being selected from the group consisting of epoxy (meth)acrylates, (meth)acrylated oils, (meth)acrylated epoxidized oils, polyester (meth)acrylates, aliphatic or aromatic polyurethane (meth)acrylates, polyacrylic acid (meth)acrylates, polyacrylate esters (meth)acrylates and mixtures thereof, and
said radically curable (meth)acrylate monomers being selected from the group consisting of mono(meth) acrylates, di(meth)acrylates, tri(meth)acrylates, tetra(meth)acrylates, penta(meth)acrylates, hexa(meth)acrylates and mixtures thereof;
ii) from about 4 wt. % to about 20 wt. % of one or more photoinitiators of formula (I):
wherein Q has the following formula (IIa), (IIb) or (IIc):
wherein n is equal to or bigger than 1, R1 are identical or different from each other and are selected from the group consisting of hydrogen and C1-C3-alkyl groups, R2 are selected from the group consisting of hydrogen and C1-C3-alkyl groups, and wherein the sum a+b+c is between 3 and 12 and the sum d+e+f+g is between 4 and 16,
iii) from about 1 wt. % to about 15 wt. % of one or more amino containing compounds selected from the group consisting of aminobenzoate compounds having a weight average molecular weight of at least 400 g/mol eq PS, amine modified polyether based acrylates having a weight average molecular weight of at least 400 g/mol eq PS and combinations thereof, and
iv) from about 1 wt. % to about 30 wt. % of one or more inorganic pigments and/or one or more organic pigments, and
v) from about 0.5 wt. % to about 10 wt. % of one or more fillers and/or extenders, selected from the group consisting of carbon fibers, talcs, micas, wollastonites, clays kaolins, carbonates, silicates, sulfates, titanates, alumina hydrates, silica, montmorillonites, graphites, bentonites, vermiculites, wood flours, quartz flours, natural fibers, synthetic fibers and combinations thereof,
the weight percents being based on the total weight of the UV-LED radically curable offset printing ink.

### Claim 2 (depends on 1)

The UV-LED radically curable offset printing ink according to claim 1, wherein at least one of the one or more photoinitiators is of formula (I) and wherein Q has the following formula (IIb-1), (IIb-2) or (IIb-3):
with n being equal to 1, 2 or 3 and with the sum a+b+c being between 3 and 12.

### Claim 3 (depends on 1)

The UV-LED radically curable offset printing ink according to claim 1, wherein the one or more amino containing compounds are selected from the group consisting of aminobenzoate compounds having a weight average molecular weight of at least 700 g/mol eq PS, amine modified polyether based acrylates having a weight average molecular weight of at least 700 g/mol eq PS and combinations thereof.

### Claim 4 (depends on 1)

The UV-LED radically curable offset printing ink according to claim 1, wherein the one or more amino containing compounds are selected from the group consisting of aminobenzoate compounds.

### Claim 5 (depends on 4)

The UV-LED radically curable offset printing ink according to claim 4, wherein the one or more amino containing compounds are selected from the group consisting of aminobenzoate compounds having the formula (III):
wherein m is bigger than 1, and wherein the sum h+i+j+k is between 3 and 12.

### Claim 6 (depends on 1)

The UV-LED radically curable offset printing ink according to claim 1, wherein the one or more inorganic pigments and the one or more organic pigments independently have a particle size of less than or equal to 5 μm.

### Claim 7 (depends on 1)

The UV-LED radically curable offset printing ink according to claim 1, further comprising one or more waxes.

### Claim 8 (depends on 1)

A process for printing a feature on a substrate by an offset printing process comprising the steps of:
a) applying the UV-LED radically curable offset printing ink recited in claim 1 by offset printing so as to form an ink layer, and
b) exposing the ink layer to UV light at a dose of at least 150 mJ/cm2.

### Claim 9 (depends on 8)

The process of claim 8, wherein the step b) consists of exposing the ink layer to one or more wavelengths between about 355 nm and about 415 nm.

### Claim 10 (depends on 1)

A use of the one or more photoinitiators recited in claim 1 in an amount from about 4 wt. % to about 20 wt. % and the one or more amino containing compounds in an amount from about 1 wt. % to about 15 wt. % for producing a UV-LED radically curable offset printing ink having a viscosity in the range of about 2.5 to about 25 Pa s at 40° C. and 1000 s−1, said UV-LED radically curable offset printing ink being suitable for printing one or more features on a security document, said UV-LED radically curable offset printing ink comprising from about 10 wt. % to about 80 wt. % of radically curable (meth)acrylate compounds, from about 1 wt. % to about 30 wt. % of one or more inorganic pigments and/or one or more organic pigments and from about 0.5 wt. % to about 10 wt. % of one or more fillers and/or extenders, the weight percents being based on the total weight of the UV-LED radically curable offset printing ink.

### Claim 11 (depends on 1)

A printed feature consisting of a cured ink layer made from the UV-LED radically curable offset printing ink recited in claim 1.

### Claim 12 (depends on 11)

A security document comprising a substrate and one or more printed features recited in claim 11.

### Claim 13 (depends on 12)

The security document according to claim 12, wherein the one or more printed features have a total surface larger than or equal to about 50%.

### Claim 14 (depends on 12)

The security document according to claim 12, wherein the substrate is a non-fluorescent substrate.

### Claim 15 (depends on 1)

The UV-LED radically curable offset printing ink of claim 1, wherein said radically curable (meth)acrylate oligomers are selected from the group consisting of epoxy (meth)acrylates, polyester (meth)acrylates, aliphatic or aromatic polyurethane (meth)acrylates and mixtures thereof; and
wherein said one or more fillers and/or extenders are selected from the group consisting of carbonates, silicas, talcs, clays and mixtures thereof.

### Claim 16 (depends on 4)

The UV-LED radically curable offset printing ink according to claim 4, wherein the one or more amino containing compounds are compounds comprising 4-dialkylaminobenzoate.

### Claim 17 (depends on 5)

The UV-LED radically curable offset printing ink according to claim 5, wherein m is between 1 and 4.

### Claim 18 (depends on 6)

The UV-LED radically curable offset printing ink according to claim 6, wherein the one or more inorganic pigments and the one or more organic pigments independently have a particle size of less than or equal to 3 μm when measured using a granulometry gauge.

### Claim 19 (depends on 7)

The UV-LED radically curable offset printing ink according to claim 7, wherein the one or more waxes are selected form the group consisting of paraffin waxes, polyethylene waxes, fluorocarbon waxes, polytetrafluoroethylene waxes carnauba waxes and mixtures thereof.

### Claim 20 (depends on 8)

The process for printing a feature on a substrate according to claim 8, wherein exposing the ink layer to UV light is performed at a dose of at least 200 mJ/cm2.